[FIX] Mumble URL in service card

allianceauth/services/modules/mumble/templates/services/mumble/mumble_service_ctrl.html

@@ -7,7 +7,9 @@
 {% endblock %}
 
 {% block url %}
-    <a href="{{ service_url }}">{{ service_url }}</a>
+    {% if username != '' %}
+        <a href="mumble://{{ connect_url }}">{{ service_url }}</a>
+    {% endif %}
 {% endblock %}
 
 {% block user %}